1. Field of the Invention
This invention relates to a double-retaining connector in which each terminal is retained in a double manner not only by an elastic retaining arm, provided within a terminal receiving chamber, but also by a spacer inserted across the terminal receiving chamber.
2. Related Art
Usually, an elastic retaining arm (hereinafter referred to as "lance") for preventing withdrawal of a terminal is provided within each terminal receiving chamber of a connector. However, the dimensions of the lance are limited, for example, because of a compact design of the connector, and therefore the lance often fails to provide a sufficient force to retain the terminal. In such a case, a terminal retainer separate from the lance is additionally used to retain the terminal in a double manner, thereby enhancing the retaining effect.
A double-retaining connector of this type disclosed in Japanese Patent Unexamined Publication No. 5-144499, in which a terminal retainer is inserted into terminal receiving chambers to retain terminals in a double manner, will now be described with reference to FIG. 4. FIG. 4 is an exploded perspective view of the conventional double-retaining connector provided with the spacer.
Two (upper and lower) rows of juxtaposed terminal receiving chambers 3 are formed in a connector housing 1, and each terminal receiving chamber 3 is provided with a lance (not shown) for primarily retaining a terminal 5. A cavity 7 is formed at a central portion of the connector housing 1 across the terminal receiving chambers 3, and the cavity 7 is open to an upper surface la of the connector housing 1. A terminal retainer (hereinafter referred to as "spacer") 11 is inserted into the cavity 7, and the spacer 11 is of a grid configuration having a plurality of juxtaposed openings 9. The spacer 11 is inserted into the cavity 7 in a two-stage manner, that is, in a provisionally-retained condition and a completely-retained condition, and in the provisionally-retained condition, each terminal 5 can pass through the associated opening 9, and then the spacer is further inserted to be brought into the completely-retained condition after the terminals 5 are thus inserted. The opening portion 9 has a terminal retaining portion 13 projected toward the center of the opening 9, and the terminal retaining portion 13 is engaged in a retaining hole 15 formed in the terminal 5.
In the double-retaining connector of this construction, for retaining the terminals 5 in a double manner, the terminals 5 are first inserted into the respective terminal receiving chambers 3 with the spacer 11 in the provisionally-retained condition. As a result, each terminal 5 is primarily retained by the lance. Then, the spacer 11 is further inserted into the completely-retained condition, so that the terminal retaining portions 13 are engaged respectively in the retaining holes 15 in the terminals 5.
Thus, each terminal 5 is retained in a double manner at the two portions by the lance and the terminal retaining portion 13, thereby achieving a sufficient terminal-retaining force.
In the conventional double-retaining connector, the spacer 11 for effecting the double-retaining can be inserted into the cavity 7, and in the provisionally-retained condition, the openings 9 are aligned with the terminal receiving chambers 3, respectively, so that the terminals 5 can pass through the openings 9, respectively.
With this construction, however, in the provisionally-retained condition, the openings 9 are required to be exactly aligned with the terminal receiving chambers 3, respectively. If the openings 9 are not exactly aligned respectively with the terminal receiving chambers 3, for example, because of dimensional irregularities of the terminal receiving chambers 3 and the openings 9 and a play between the connector housing 1 and the spacer 11, steps 17a and 17b develop at regions A and B in FIG. 5, and the front end of the terminal 5 inserted in an inclined posture abuts against the step 17a, 17b (see FIG. 6), which results in a problem that the insertion of the terminal 5 is adversely affected. Therefore, when the terminals 5 are to be inserted, for example, by an automation machine, an inserting resistance is increased for this reason, which results in a problem that an abnormal operation of the automation machine occurs.
The terminal 5, when found defective or degraded, needs to be exchanged, and at this time during the withdrawal of the terminal, the terminal 5 is liable to be engaged by steps 19a and 19b formed at regions C and D (FIG. 7), thus causing a problem that the efficiency of the operation is low.